1. Field of the Invention
The invention relates in general to data conversion systems, and more particularly, to a method and apparatus for data conversion systems using time manipulation.
2. Description of Related Art
Signal speeds for electronics have dramatically increased over the past decade. Clocking speeds for computers are routinely in the hundreds of megahertz (MHz) region, and communications systems commonly use multi-gigahertz (GHz) carrier signals. Building high-speed receivers to capture and analyze such signals has become increasingly more difficult.
Time manipulation of signals has been proposed as a possible technique to match data rates of signals to the receiver or to observe phenomena that last for only a few nanoseconds (ns), e.g., signal transients, clock edges, and nuclear explosions. Considering the time/space equivalence of dispersion and diffraction, and in direct analogy to a spatial lens, an electrical signal may be stretched (or, alternatively, contracted) in time by subjecting the electrical signal to a dispersion-quadratic phase modulation-dispersion sequence. This concept remains mostly theoretical, however, because of the difficulty of obtaining high quadratic phase modulation rates and/or large bandwidth dispersion elements.
Some prior attempts at time stretching include an all-electrical time stretch system. In the electrical domain, highly dispersive elements are available; however, the small bandwidth of these elements limits the capability and performance of an all-electrical system.
All-optical systems have large bandwidth dispersive elements, but the all-optical system has difficulty producing a high quadratic phase modulation rate. Although resonant optical phase modulation has been used to attain high modulation rates, such systems are useful for very short periods of time. Compression of electrical signals is also difficult within electrical or optical conversion systems because of the reasons listed above relating to dispersion.
It can be seen, then, that there is a need for a system that can stretch or compress a signal in time. It can also be seen then that such a system must be able to be produced with standard components to increase usage times of the compression or dispersion system.